With the patch around mid-May 2020, a couple of easter-eggs appeared. The first was red key cards started to be able to open some of the bunkers in game, exposing multiple chests and further bunker doors which currently can't be opened. The second is a special set of steps to open the 11th bunker at the top of the map, with chests, extra blueprints & a nuke. Here is a great video explaining this by youTuber "MrDalekJD" : To help, I have broken down the video into the important parts below. Ringing Phone 1 : Ringing Phone 2 : Ringing Phone 3 : Ringing Phone 4 : Ringing Phone 5 : Ringing Phone 6 : Ringing Phone 7 : Ringing Phone 8 : Russian 0 - 9 - video with pronunciations below Phone 0 : Phone 1 : Phone 2 : Phone 3 : Phone 4 : Phone 5 : Phone 6 : Phone 7 : Phone 8 : Phone 9 : Bunker 11 location - video below map: